Just loaded a number of 38 specials and then switched to my .357 mag dies. I see that I am almost out of magnum primers but have a ton of standard primers. How important is using magnum primers for my .357 loads? Can I just use standard primers???

Primer choice mostly depends on how easy the powder is to ignite. Also how tightly packed it is and the powder's burn rate. Some of it is fairly easy to understand and some of it seems like magic.

I will not try to school you on the principles, lest I be wrong. I hedge my choices by reading as many different manuals as I can and seeing what primers are chosen for what powders in what velocity ranges and bullet weights.

It was alluded to above ... but using magnum or standard primers has nothing at all to do with a 'magnum' cartridge. It all comes down to what 'powder' you are using. Some powders are primer insensitive ... like Unique and Universal. Others like 4227 or H-110 require a magnum primer. And some powders like 2400 you see a big velocity (pressure) swing when switching primer types... Anyway, in your case my preferred primer is standard with Unique/Universal.

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A clinger. When guns are outlawed, only outlaws will have guns. Single Action .45 Colt (Sometimes improperly referred to by its alias as the .45 'Long' Colt or .45LC). Don't leave home without it. Ok.... the .44Spec is growing on me ... but the .45 Colt is still king.

Wow, just looked and I have a 1997 book! Now, I'm concerned about these loads.

Why? Do you think that the burning rate is different now? I frequently hear a lot of talk about "new" 2400 being faster than "old" 2400, etc.. With all the load data published for that propellant since it's introduction, how big a product liability exposure do you thing it would be if the manufacturer arbitrarily starts dinking with the burning rate??? Canister grade propellants are canister grade for a reason and the manufacturers cannot just "VOID" previously published load data. They may try some day but things just do not work that way.

Because published load data is a collection of test results taken on a specific day with a specific firearm or pressure barrel with specific lots of components used under specific atmospheric conditions at that elevation above sea level. This stuff does not come down from a burning bush etched on granite tablets. This is not exact science and you use the data at your own risk-as noted by the many disclaimers on component containers and in reloading manuals. As a matter of fact, info such as exact component type and brand along with the firearm or test fixture used and the COAL are furnished only as a way to qualify the parameters under which the data was obtained and in no way guarantee functional utility.

I'm sure that handloaders sometimes lose sight of what those numbers in the books and on the websites really are and what they really mean, hence the rules such as Handloader's Rule #1-when starting load development, changing any component in an existing load or using a load in a different gun, start low and work up.

BruceM, I'm not sure what your rant is about. The new published MAX load is more that 10% less than what was previously published...this gives me pause. I never get up to max loads without working up - if I see evidence of excessive pressure (primer blow outs, bulging cases, etc.), I back off immediately. I always err on the side of safety.

The new published MAX load is more that 10% less than what was previously published

So, what you're saying is that either the "new" powder is substantially faster or the old data produced a substantially overpressure load?

Possibly I didn't articulate the reasons for that in my "rant". That said, I do not wish to restate the reasons.

Incidentally, there are many folks you feel the reason for reduction in published charge weights of old propellants is directly proportional to the degree of involvement of the legal and underwriting departments have in the publishing process-a theory I agree with to varying extents.

Quote:

I never get up to max loads without working up - if I see evidence of excessive pressure (primer blow outs, bulging cases, etc.), I back off immediately. I always err on the side of safety.

That's always a good plan of attack. Be advised that when you get to the point of primer blow outs, bulging cases, etc., you are already way past the safe point and further, there will be no "classic" signs of high pressure in lower intensity rounds such as .38 Special, .45 Colt and .45 ACP until your stratospherically over the edge. In those cases, the chronograph becomes your good friend.

The new published MAX load is more that 10% less than what was previously published...this gives me pause.

Lawyers, improved testing equipment, weaker firearms found for a particular cartridge that came from 1880 or Pakistan I don't know
BruceM brings up some good points.
If a powder manufacturer changes the burn rate or deviates from the grain per cubic centimeter beyond spec they would need to call that powder by a different name.

I just ran some Quickload calculations. 8.4 grains of Universal is pushing it (35800+ psi) 8.8 is too much (39000+ psi) That's assuming Hornady XTP/HP's loaded 1.59" OAL. If you load them shorter, the pressure will be higher. Same calcs using Remington 125 grain SJHP's were 2000 psi higher.

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"The only way to stop a bad guy with a gun is with a good guy with a gun"

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